1. Field of the Invention
This invention relates to apparatus for testing a chemical and more particularly to an apparatus for testing the effect of an antibiotic on bacterial or biochemical substances.
2. Description of the Prior Art
U.S. Pat. No. 4,076,592 issued to the present applicant discloses and claims a method and apparatus for testing the effect of an antibiotic on a liquid suspension of a bacterial or a biochemical substance. Basically, the apparatus disclosed and claimed in the referenced patent includes a reservoir carried by a substantially planar base, the reservoir being separated by a barrier from each of a plurality of side-by-side test chambers also carried by the base. Each test chamber has an antibiotic or biochemical substance disposed therein, and each test chamber is separated from the next-adjacent test chamber by a side wall having a height greater than the height of the barrier. A clear plastic cover is provided to enclose the reservoir and the test chambers so that fluid communication is permitted only between each individual test chamber and the reservoir through a clearance space defined between the interior of the cover and the top of the barrier.
After introduction of a liquid suspension containing the substance to be tested within the reservoir, the method of testing the antibiotic includes the rotation of the apparatus about an axis of rotation parallel to or coincident with an axis extending longitudinally through the reservoir to permit the substance being tested to enter into each of the test chambers from the common reservoir through the clearance defined between the top of each barrier and the interior of the cover. In this manner, the necessity of introducing the substance to be tested into each of the test zones is avoided. Of course, the effect of any chemical substance on any other chemical substance may be tested utilizing the apparatus and method of the referenced patent and this application.
Although the apparatus disclosed in U.S. Pat. No. 4,076,592 is advantageous in that it obviates the need for introduction of the substance be tested individually into each of the test chambers, it appears that care must be exercised during the rotation of the apparatus in order to insure that the substance to be tested is introduced over the barrier from the reservoir into each of the test chambers. It has been observed that any inadvertent tilting or canting of the apparatus during the rotative step may result in the substance not being introduced into certain of the test chambers. This result follows due to the natural tendency of the liquid to respond to the inadvertant tilt of the apparatus by collecting adjacent one end thereof. Thus, during rotation, certain of the test chambers may not receive the liquid suspension of bacteria under test, and the substances in those chambers would not be exposed thereto.
It would therefore appear to be of advantage to provide an apparatus for the testing of a liquid having a chemical substance therein wherein the common reservoir of the apparatus includes an array of guide walls disposed so as to define a channel associated with each test chamber such that the tendency of the liquid to flow to one end of the apparatus in response to inadvertent tilting during the rotative step is avoided and such that the liquid flow is channelized from the reservoir into each test chamber.